Class D amp long term reliability

[Doodski]

it's a cheap insurance and the fans are very quiet so it wouldn't hurt. My 10yr old Denon x4000 AVR in the living room still run like a champ and it is cooled by two 140mm 18dB USB fans sat on top of the AVR since day 1. I use the same USB fan to cool my RT-AC5300 router and saw a 30 degree temperature drop as well. lol

Speaking of long term class D reliability and PWM operation I guess it's near time to dust out the cabinet(s) and blow off the coolers. I vacuumed and stuff last week... Summer is coming and I might get the urge to snipe stuff and I expect my gaming box to always be operational.

USB forced air cooling is a great way to extend the life of gear. For sure.

 

[EJ3]

Hate to see what you find value in in cars and some other stuff if a very few years of amp works. Throw away society indeed. Especially NAD (Not always dependable)

My NAD 2200's have been working just fine since they were built.
Then I sent them for refurbishment/resto-mod because I thought something "MIGHT" go wrong after 35 or 40 years of service.
After that AMIRM tested one of my 3 & this was the result:

Per Amirm (on one of my personal NAD 2200's):

Note the differences in the frequency response plot and the SINAD.
They are both better when you run it using the LAB INPUTS (that is true whether you are running bridged mono or not) :

NAD 2200 Vintage Amplifier Review​

Wow, we have one kilowatt of power coming out of this amp in short duration!

I was surprised that the frequency response was not flat but was relieved to see later in the thread that this is due to insertion of low and high pass filters. So here is the frequency response with Lab input that doesn't have such a filter:

Response now (in green) as it should be, ruler flat to below 10 Hz, and well extending past the 40 kHz limit of this measurement.

I figured the filters may be adding some noise/distortion so re-ran the dashboard again:

Distortion doesn't change but if you look at the noise floor at 20 Hz, it is down by some 10 dB. That improves SINAD a couple of dBs, making the amplifier stand out even more!

Zoomed:

And signal to noise ratio:

Conclusions
Nice to see innovation like this from equipment that is over 30 years old! Shame on manufacturers that produce amplifiers for much less power, more distortion and higher prices these days. No, you don't get a fancy case here and sheet metal is strictly budget category. But you are not going to sit on the amp. The guts are where it matters and NAD 2200 delivers.

NOTE: the output relay on stock 2200 gets corroded and fails over time. There are videos and DIY threads on how to upgrade the relay there to fix the problem. The unit tested here has that fix. Other than that, there are not reports of many other reliability issues even though NAD products are often said to be less reliable than other brands.

Overall, I am happy to recommend the NAD 2200. I almost gave it the highest honors but given the upgraded nature of the test unit, and the fact that used amps may have issues, I avoided that. But you could have easily pushed me to give it the golfing panther

 

[zdykstra]

Before I bought my pair of AHB2s, I looked at NAD, Bel Cantro and Elac amps, all class D, my concern was reliability, my C-J amp had run for 25+ yrs without a hiccup, but I sold it in a moment of weakness. The Class D amps I had actually seen and heard, all failed within the first year. So I wanted an amp with a dealer network and at least a phone number to call. All of the failed amps, were bought off the web, the first one sound great, the others bought them, then 7-9 months later they started to die. I do not know who the manufacturer was, but they could get no service or repairs, they ended up in the landfill. It encouraging to hear they can actually be reliable. I’m hoping I’ll never new new amps, but it’s nice to know there are other viable options.

For what it's worth, I have a pair of Bel Canto REF500M amps that have been on 24/7 for 9 years, give or take. I also have a pair of self-built ICEPower 125asx2 amps that have been on 24/7 for around 7 years. They've never once given me an ounce of trouble.

 

[egellings]

Most things follow a bathtub curve for failure, with increased failure rate right at the start of an life after initial delivery and then after an interval as end of life approaches (or as time for major overhaul approaches). The length between the two peaks is, however, variable and higher quality items can be expected to push the end further away from the beginning. And there are always random failures.

It's those darn cosmic rays, dag nab it!

 

[EJ3]

Speaking of long term class D reliability and PWM operation I guess it's near time to dust out the cabinet(s) and blow off the coolers. I vacuumed and stuff last week... Summer is coming and I might get the urge to snipe stuff and I expect my gaming box to always be operational.

USB forced air cooling is a great way to extend the life of gear. For sure.

Now that I am getting ready to mount 3 of my 6 NAD 2200s in a WELL VENTILATED CABINET, just as insurance, I'll also get myself 3 of these USB coolers to make sure that the air flow is going where it needs to go.

 

[EJ3]

I would posit that keeping electronics turned on seems to encourage longer life, the on/off cycle itself seems to be a major form of internal wear on a whole bunch of components - it isn't exclusive to Class-D.

My Class-D Crown XLS2500's have been on 24/7 since around 2013... and I purchased them second hand.... they seem quite intact and running "like new"
But then my Quad 606 and 707 amps, have had a similar regime since around 2000.... both were purchased used, the 606 had a refurb around 2005 - mostly to match its input sensitivity to the 707 - the 606 is a late 80's model, the 707 90's... - they are perfectly happy soldiering on too!

There is a degree of give and take needed - additional cost of keeping them on when "idling" - vs the cost of replacement or refurbishment....

I 've gone both ways, leaving them on you are subject to random power spikes (1 took out one of my APC's & one of my 2 NAD 2200's that were on that circuit. There were other thing on that circuit that were fine. Perhaps those two items absorbed enough of the punch of the surge that it did not bother the second NAD 2200, the APT/Holman Preamp or the Technics SL-M3 TT that were on the same circuit (all but the TT had been on for a number of years). The only thing wrong with the NAD2200 was the speaker relay (40 amp one) quit functioning, a rather easy fix. There was a flash large enough to cast shadows when it occurred, so it was a pretty good jolt of power.
On the other hand, turning stuff off & on gives them many small jolts that add up.
So you makes your choices & takes your chances.

 

[EJ3]

View attachment 365479


Just for experiment, My Apollon 1ET7040 case went from 105F down to 86F using the lowest fan setting from my laptop pad cooler, that's close to 20 degree drop. Measured the Apollon front, bottom, and top section with an infrared temperature gun, i figured since these Hypex/Purify amps are using convection heat transfer via the case, keeping it as cool as possible may be able to prolong the life of amp?

These laptop cooling pads are cheap, like $20~30 from Amazon, most of them are very quiet, anywhere between 25dB to 35dB depending on the fan speed and mode, and it cools both my AVR and the Apollon at the same time when I stacked them together.

View attachment 365485

Amazon.com

Amazon.com

I just ordered 4 of those. The dimensions seem perfect for what I am doing. Thank you for pointing those out, as I had been looking for some but had not hit upon those. EJ3

 

[Doodski]

Now that I am getting ready to mount 3 of my 6 NAD 2200s in a WELL VENTILATED CABINET, just as insurance, I'll also get myself 3 of these USB coolers to make sure that the air flow is going where it needs to go.

A reliable steady stream of fresh cooling air is all that is requested. I run 4, 200mm blue LED fans also with 2, 140mm coolers.

 

[dlaloum]

I 've gone both ways, leaving them on you are subject to random power spikes (1 took out one of my APC's & one of my 2 NAD 2200's that were on that circuit. There were other thing on that circuit that were fine. Perhaps those two items absorbed enough of the punch of the surge that it did not bother the second NAD 2200, the APT/Holman Preamp or the Technics SL-M3 TT that were on the same circuit (all but the TT had been on for a number of years). The only thing wrong with the NAD2200 was the speaker relay (40 amp one) quit functioning, a rather easy fix. There was a flash large enough to cast shadows when it occurred, so it was a pretty good jolt of power.
On the other hand, turning stuff off & on gives them many small jolts that add up.
So you makes your choices & takes your chances.

I run the setup through a Belkin PureAV "conditioner" - so that removes most of the risk of spikes...

 

[EJ3]

I run the setup through a Belkin PureAV "conditioner" - so that removes most of the risk of spikes...

That is what the APC Uninterrupted power supply was for.
But it blew up massively & what got through wastook the relay ou in one of the NAD's. But everything else that was pluged into that survived.
This was the largest UPC that I have seen without ordering it from a supply house.
My stereo is on two of these (only one blew up, & only the relay was taken out in one of the 2 NAD's in it.
The shadow of the flash could be seen over 50 ft away in another room that I was in.
I thought that a power pole transformer had blown up on the pole outside the house, such was the explosive noise.
My refrigerator is on another one of them.
It will run the refrigerator a couple of days if there is ZERO power from the mains.

 

[MCH]

Fan subject.
I always wonder if the benefits or using a fan and having the components a bit cooler is not countered by bringing more dust to the inside and risking an electrical failure in the long term.

I am talking about the case when a fan is not absolutely necessary, obviously.

Anyone with an informed opinion?

Note that opening the device to clean the dust from time to time also brings some additional risk.

 

[im_gumby]

Just for experiment, My Apollon 1ET7040 case went from 105F down to 86F using the lowest fan setting from my laptop pad cooler, that's close to 20 degree drop. Measured the Apollon front, bottom, and top section with an infrared temperature gun, i figured since these Hypex/Purify amps are using convection heat transfer via the case, keeping it as cool as possible may be able to prolong the life of amp?

These laptop cooling pads are cheap, like $20~30 from Amazon, most of them are very quiet, anywhere between 25dB to 35dB depending on the fan speed and mode, and it cools both my AVR and the Apollon at the same time when I stacked them together.

You don't really need to do much other than have good airflow around the equipment.
There's also a bit of luck in terms of the components themselves.
They'll usually last longer than the warranty, but some will last far longer.

 

[im_gumby]

I 've gone both ways, leaving them on you are subject to random power spikes (1 took out one of my APC's & one of my 2 NAD 2200's that were on that circuit. There were other thing on that circuit that were fine. Perhaps those two items absorbed enough of the punch of the surge that it did not bother the second NAD 2200, the APT/Holman Preamp or the Technics SL-M3 TT that were on the same circuit (all but the TT had been on for a number of years). The only thing wrong with the NAD2200 was the speaker relay (40 amp one) quit functioning, a rather easy fix. There was a flash large enough to cast shadows when it occurred, so it was a pretty good jolt of power.
On the other hand, turning stuff off & on gives them many small jolts that add up.
So you makes your choices & takes your chances.

You can pick up a Tripp Lite or some thing similar that handles surge and brown out line conditioners. (No battery backup)
This will help w line spikes. Its not 'audio grade' line conditioning, but works well enough. The only drawback... if you have lousy power... you'll hear the clicking of the units switching and you can see if its surges or brown outs. Saved my butt recently. I had just moved back to Chicago and in our new Condo, our electrical panel had a short in it.
So we'd have some major power issues. The only way I knew we had problems was thru that clicking so I could monitor the lights on the units.

 

[EJ3]

You can pick up a Tripp Lite or some thing similar that handles surge and brown out line conditioners. (No battery backup)
This will help w line spikes. Its not 'audio grade' line conditioning, but works well enough. The only drawback... if you have lousy power... you'll hear the clicking of the units switching and you can see if its surges or brown outs. Saved my butt recently. I had just moved back to Chicago and in our new Condo, our electrical panel had a short in it.
So we'd have some major power issues. The only way I knew we had problems was thru that clicking so I could monitor the lights on the units.

I live on 3/4 acre on a deep water creek (44 ft 13 & 3/4 ton boat id not an issue at my dock with shore power available to it.
Whatever the electrical surge was, it blasted the peoples stone chimney next door hard enough for the mortar to crack.
The APC Uninterruptable Power Supply is a 1300 VAmp unit.
I have 6 of these units, as well as numerous smaller ones throughout my home.
They are the sacrificial element in most of my circuits

• 

APC UPS 1350VA UPS Battery Backup and Surge Protector, BX1350M Backup Battery Power Supply, AVR, Dataline Protection​

Brand	APC
Battery Cell Composition	Lead Acid
Product Dimensions	19.3"D x 13.6"W x 9"H
Color	Black
Material	1

• 1350VA / 810W battery backup power supply
• 10 Outlets (NEMA 5-15R): 5 surge protector with battery backup; 5 outlets with Surge Protection Only
• 1 GB network dataline protection, 6' Power Cord, right-angle 3-prong wall plug (NEMA 5-15P), and free Windows PC power-management software (Mac OS uses native "Energy Saver" Settings)
• Automatic Voltage Regulation (AVR): instantly corrects low/high voltage fluctuations without discharging the battery, and is Active PFC compatible
• Replaceable Battery and Energy-Star Certified: The battery can be replaced with APC replacement battery model APCRBC123 (sold separately). This UPS meets the Energy Star Requirements for product specification: Uninterruptible Power Supplies (UPS)

 

[EJ3]

A reliable steady stream of fresh cooling air is all that is requested. I run 4, 200mm blue LED fans also with 2, 140mm coolers.

I got mine today. It will be some months before the system is up & running but they fit into place quite nicely.
I ended up getting the same ones Xcaliber has:
https://www.amazon.com/dp/B0CP58Z4CP?ref=ppx_yo2ov_dt_b_product_details&th=1

 

[Doodski]

I got mine today. It will be some months before the system is up & running but they fit into place quite nicely.
I ended up getting the same ones Xcaliber has:
https://www.amazon.com/dp/B0CP58Z4CP?ref=ppx_yo2ov_dt_b_product_details&th=1

Wowow! 15 LED fans. Very gazoingK! I actually prefer the illumination at nights and to see in my cabinets.

 

[EJ3]

Wowow! 15 LED fans. Very gazoingK! I actually prefer the illumination at nights and to see in my cabinets.

You can color code the lights so that when you DO let the smoke out of wires, as the MAGIC goes away, it will do it to pretty colors!

 

[dlaloum]

Fan subject.
I always wonder if the benefits or using a fan and having the components a bit cooler is not countered by bringing more dust to the inside and risking an electrical failure in the long term.

I am talking about the case when a fan is not absolutely necessary, obviously.

Anyone with an informed opinion?

Note that opening the device to clean the dust from time to time also brings some additional risk.

From my experiences with PC's - I totally agree... over time the fans pull in dust that gets deposited as a nice warm rug on all the electronics...

Hence I have a strong preference for designs that are passively cooled... and if fans are involved, I like to see them at their lowest minimum speeds (or possibly turned off) with normal SPL's.

The Crowns I have, keep the fans off or at sufficiently low speed that I am completely unaware of their being on... my normal usage SPL's almost never get as high as 4W.... (out of the 440W the amps are capable of)... which naturally keeps the fans at the lowest settings.
I don't know whether the baby brother XLS1000 (as opposed to my XLS2500) would also keep the fans at such a low speed or off... given that for the same SPL it would be using more than double the proportion of its rated power....

Perhaps another good reason for massive overkill in amp power?

P.S. - I built a completely passively cooled HTPC for my setup - using a substantial heatsink case, with heatpipes connecting the CPU/GPU to the heatsinks... it never gets more than warm

 

[Xcaliber]

Fan subject.
I always wonder if the benefits or using a fan and having the components a bit cooler is not countered by bringing more dust to the inside and risking an electrical failure in the long term.

I am talking about the case when a fan is not absolutely necessary, obviously.

Anyone with an informed opinion?

Note that opening the device to clean the dust from time to time also brings some additional risk.

it's a good idea to use compressed air to clear out any dust collected in the AVR while you clean the USB fans, depending on how dusty the environment is, personally i clean mine once a year since we have a few air purifiers running in the house, just to minimize airborne dust for healthier air, etc.

Wowow! 15 LED fans. Very gazoingK! I actually prefer the illumination at nights and to see in my cabinets.

The LED and RGB light strips look pretty snazzy lol you can also turn it off if it's too distracting as well.

I got mine today. It will be some months before the system is up & running but they fit into place quite nicely.
I ended up getting the same ones Xcaliber has:
https://www.amazon.com/dp/B0CP58Z4CP?ref=ppx_yo2ov_dt_b_product_details&th=1

it's working pretty well for me so far, perfect size to cool both the AVR and the Apollon amp, it's very quiet to boot. BTW, if you hold down the power button, you can cycle through three different fan mode, on top of 6 different fan speed to choose from.

 

[EJ3]

it's a good idea to use compressed air to clear out any dust collected in the AVR while you clean the USB fans, depending on how dusty the environment is, personally i clean mine once a year since we have a few air purifiers running in the house, just to minimize airborne dust for healthier air, etc.



The LED and RGB light strips look pretty snazzy lol you can also turn it off if it's too distracting as well.



it's working pretty well for me so far, perfect size to cool both the AVR and the Apollon amp, it's very quiet to boot. BTW, if you hold down the power button, you can cycle through three different fan mode, on top of 6 different fan speed to choose from.

Thanks for the power button tip.
I used one last night under my 2011 Dell STUDIO XPS 16 Laptop (the only Laptop that I own, running Windows 10 Enterprise 64 Bit)
Intel Core i7 940 XM (4 Core)
8 GB DDR3 @ 663 Hz RAM
1 TB Samsung EVO 840 SSD
Matshita BD-RE UJ235A Yes, it plays Blu Ray's (it has an HDMI OUT & 2 USB 3.0, 2 USB 2.0 Ports and can both Play & Record DVD's & CD's)
AMD HIGH DEFINITION AUDIO DEVICE
It kept it cool while doing some intensive amount of updates (according to the computer, it had not been connected to the internet in 243 days).